Weak ferromagnetism in the ferroelectric BiFeO3–ReFeO3–BaTiO3 solid solutions (Re=Dy,La)

Abstract

The binary and ternary solid solutions, BiFeO3–BaTiO3, BiFeO3–ReFeO3–BaTiO3 (Re=Dy,Pr,La), and BiFeO3–BaFeO2.5–BaTiO3 have been explored for attaining ferromagnetic ferroelectrics in bulk ceramics and understanding the effect of rare earth orthoferrites ReFeO3 on the spontaneous magnetization. The coexistence of ferromagnetism and ferroelectricity has been observed over the composition range of 0.2⩽x⩽0.4 in the (1−x)BiFeO3–xBaTiO3 at room temperature. The introduction of DyFeO3 and LaFeO3 expands the composition range of the coexistence. The most superior ferromagnetic ferroelectrics obtained in this study are the 0.65BiFeO3–0.025DyFeO3–0.325BaTiO3 (Pr=5 μC/cm2,Mr=0.1 emu/g), 0.4875BiFeO3–0.025DyFeO3–0.4875BaTiO3 (Pr=7 μC/cm2,Mr=0.06 emu/g), and 0.475BiFeO3–0.05LaFeO3–0.475BaTiO3 (Pr=3.2 μC/cm2,Mr=0.2 emu/g). The spontaneous magnetization strongly depends on both the type and amount of the substitution components, DyFeO3, LaFeO3, PrFeO3, and BaFeO2.5 rather than the degree of G-type antiferromagnetic ordering. The origin of the spontaneous magnetization has been discussed in terms of antiferromagnetic ordering and charge carrier mediation.

Dielectric, electrical conduction and magnetic properties of multiferroic Bi0.8Tb0.1Ba0.1Fe0.9Ti0.1O3 perovskite compound

“…Recently, several researchers reported multiferroic perovskite ceramics such as antiferromagnetic-ferroelectric and antiferromagnetic/weak ferromagnetic-ferroelectric systems. 4,5 As a typical ferroelectromagnetic material, BiFeO 3 (BFO) is the most useful one from the practical application point of view owing to its high Curie (T C ¼ 1103 K) and Neel (T N ¼ 643 K) transition temperatures, and therefore it has involved a great deal of research interest. 6 Because of the canting of the Fe sublattice moment, BiFeO 3 shows a weak magnetic moment at room temperature.…”

Structure and some magnetic properties of (BiFeO3) x -(BaTiO3)1−x solid solutions prepared by solid-state sintering

“…It may be added that the remnant magnetization 0.5 emu/g corresponding to   2.7 × 10 −2  B /f.u. measured for our solid solutions is almost an order of magnitude higher than that from literature (0.08 emu/g) [10]. Moreover, coercivity  400 kA/m (5 kOe) is signifi cantly higher than that measured for typical (BiFeO 3 ) x -(BaTiO 3 ) 1-x solid solutions (1.3-3.4 kOe) [7].…”

Compositional dependence of hyperfine interactions and magnetoelectric coupling in (BiFeO3)x-(BaTiO3)1–x solid solutions

“…Moreover, the volume of the rhombohedral unit cell increases as the concentration of BaTiO 3 increases due to the difference between the ionic radii of Bi 3+ (103 pm) and Ba 2+ (135 pm). The gradual structural transformation of (BiFeO 3 ) x -(BaTiO 3 ) 1-x has been described in many research papers [6][7][8][9][10][11][12][13][14], however, its confi rmation by the Rietveld method has been demonstrated in only a couple of them [8,11].…”